Broad beam attenuation of 70-250 kv. p. x-ray beams in aluminum.

Abstract

The necessity of using broad beam attenuation data for planning x-ray protection has already been pointed out (1). Beams at least 3 feet in diameter at the barrier must be employed if useful data are to be obtained. For studies of the attenuation of low-voltage beams, it is difficult to make and handle large, thin sheets of concrete. Miller and Kennedy (2) recently called attention to the fact that since attenuation of such beams in materials of low atomic number is due to Compton effect, attenuation data can be taken in other material of low atomic number (viz. aluminum), and by applying a small correction factor use can be made of these data in computing the required concrete barrier thickness. This correction factor, 1.1, remains constant over a very wide range of voltages. The attenuation of x-ray beams produced by pulsating voltages of 70, 100, 125, 150, 200, and 250 kv.p. has been measured in commercially pure aluminum. The thickness of concrete required can be computed by multiplying by 1.1 the thickness of aluminum necessary for the required attenuation,